iOS Interview Questions 2020 - Part 2

Questions, Tips and Tricks to clear iOS Interview Questions

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If you did not have a chance to read the first part of this blog, please read here

Q1. What will be the output

func someFunction() -> String {  
     defer { return "World" }
     return "Hello"  
}

print(someFunction())

Q2. What will be the output

var employeeSalary = 20

func updateEmployeeSalary() {  
   employeeSalary = 70
   
   defer { employeeSalary = 30 }  
   defer { employeeSalary = 40 }  
   defer { employeeSalary = 50 }
   
   employeeSalary = 50  
}

updateEmployeeSalary()
print(employeeSalary)

Q3. Which of these is not a valid execution for the below code

var a: String = "a"  
var b: String! = "b"  
var c: String? = "c"
a = c // 1  

b = c // 2  
c = b // 3

Q4. Let’s say we have 3 views of given Intrinsic size

In the below given horizontal StackView. Which of the following is true?

Q5. Let’s say we have 3 views of given Intrinsic size

arranged in a horizontal StackView, Which among the following represents Distribution set to fillProportionally .

Q6. What will be the output of the code snippet below:

class WhiteHouse { 
    weak var pentagon: Pentagon?
    
    deinit {  
        print("White House deinitialized")  
    }  
}

class Pentagon {
    weak var whiteHouse: WhiteHouse?
     
    deinit {  
        print("Pentagon deinitialized")  
    }  
}

var a = WhiteHouse()  
a.pentagon = Pentagon()

weak var b = Pentagon()  
b?.whiteHouse = a

Q7. What will be the output of the code snippet below:

class Kondana<T: Equatable> {
    var dictDataHolder = [String: T]() 

    func add(value: T?, using key: String) -> T? {  
        self.dictDataHolder[key] = value
        return value  
    } 
}

var fortOne = Kondana<String>()  
let value = fortOne.
print(value)

Q8. What will be the output:

var motive = "Sip"
let userMotive = { [motive] in  
    print(motive)  
}

motive = "Lump Sum"
print(userMotive())

Q9. What will the output of the code snippet below be?

struct Person {  
    var contact: Contact
    
    init(contact: Contact) {  
        self.contact = contact  
    }  
}

class Contact {  
    var phoneNumber: Int
    
    init(phoneNumber: Int) {  
        self.phoneNumber = phoneNumber  
    }  
}

let contact = Contact(phoneNumber: 1800)  
var vijay = Person(contact: contact)
let ajith = vijay  
vijay.contact.phoneNumber = 1234  

print(ajith.contact.phoneNumber)  
print(vijay.contact.phoneNumber)

Q10. Choose the output of the Following Programme:

protocol SomeProtocol {  
    func someFunction()  
}

extension SomeProtocol {  
    func someOtherFunction() {  
        print("SomeProtocol: Some Other Function")  
    } 
}

struct SomeStruct: SomeProtocol {  
    func someFunction() {  
        print("Some Function")  
    } 
    
    func someOtherFunction() {  
        print("SomeStruct: Some Other Function")  
    }  
}

let someStruct: SomeProtocol = SomeStruct()  
print(someStruct.someFunction())  
print(someStruct.someOtherFunction())

Q11. Which of the following programme(s) will print the following:

1 2 3 4 5 6 7 8 9 10 End of the World!

let firstQueue = DispatchQueue (label: "First Queue")
let globalQueue = DispatchQueue.global()
let parentQueue = DispatchQueue (label: "Parent Queue")

Q12. What is the Type of color:

enum Color: String {  
    case red  
    case green  
    case blue  
}

let color = Color(rawValue: "yellow")

Q13. Answer the following questions:

1. What is the center of outerView
   (x: ?, y: ?)

2. What is the centre of innerView
   (x: ?, y: ?)

3. What are the bounds of innerView
   (x: ?, y: ?, width: ?, height: ?)

4. What are the bounds of outerView
   (x: ?, y: ?, width: ?, height: ?)

5. What is the frame of the innerView
   (x: ?, y: ?, width: ?, height: ?)

Q14. Spot the issue in this code if any?

final class SingleTon {
    static let shared = SingleTon()  
    private var viewControllers = [UIViewController]()
    
    private init() { }  
      
    func add(vc: UIViewController) {  
        viewControllers.append(vc)  
    } 
    
    func remove(vc: UIViewController) {  
        if let index = viewControllers.firstIndex(of: vc) {  
            viewControllers.remove(at: index)   
        }  
    }  
}

final class SomeViewController: UIViewController {  
    init() {  
        super.init(nibName: nil, bundle: nil)  
        SingleTon.shared.add(vc: self)  
    }  
}

Answers are not provided intentionally 😜, to make you try and understand personally, you can add your answers/clarifications in the comment section.